Optical scanner

ABSTRACT

An optical scanner comprises a scanner housing including a scan window, a laser light source, reflected light detector and a Micro-Electro-Mechanical Systems (MEMS) mirror array arranged to produce a scan line pattern. The light from the laser source is adjustably focused by the MEMS mirror array so as to enable auto-focusing of the laser light during the scanning of a bar code.

The present invention relates to an optical scanner and morespecifically to an optical scanner having enhanced scan volume features.

BACKGROUND OF THE INVENTION

To date the problems of enhanced scan volume and increased readabilityof bar codes held at different orientations to a scanner have only beenaddressed by the use of dual aperture scanners.

Commonly assigned U.S. Pat. Nos. 5,229,588, 5,684,289, and 5,886,336disclose a typical dual aperture optical scanner. The scanning lightbeams from a laser diode pass through substantially horizontal andvertical apertures to provide more item coverage than a single aperturescanner.

Known multi-aperture optical scanners produce scan patterns with gaps initem coverage. These gaps increase as the item is moved away from anideal position in the center of the scan volume.

Therefore, it would be desirable to provide an optical scanner which isnot only capable of reading a bar code label at different orientationsto the scanner, but at different distances to the window.

Scanning bar codes which are located at different distances to thescanner, especially small bar codes such as the new RSS symbology, isextremely difficult. The problem is exacerbated by the characteristic ofpresent day bar code readers that the focal length of the scan light canvary as it traverses the scanner. This is due to the extremely complexnetwork of pattern mirrors utilized in scanners, which can result indifferent optical path lengths and therefore different focal positionsfor light passing through the scanner at different times.

The complexity of, especially dual aperture, scanners will be describedin order to illustrate another advantage of the present invention, whichis the simplicity and corresponding ease of construction of the scanner,which helps mitigate the problems detailed above.

As will be illustrated in more detail below, with reference to FIGS. 1to 6, present day scanners comprise, a laser assembly, spinner assembly,collection optics, pattern mirrors, detector assembly, electronics, awindow and scanner housing which contains all the individual assemblies.In operation, the laser beam intercepts the polygon spinner and issubsequently scanned in a single axis towards a set of pattern mirrorswhich reflect the individual scan lines out the window and onto abarcode. The laser energy is then reflected off of the barcode and aportion is gathered by the collection optics and focused onto thedetector generating a signal to be decoded by the electronics. Thepositions at which the scan lines exit the window are static, and arecontained in a relatively small portion of the hemispherical volumeavailable outside and adjacent to the window (FIG. 6). Consequently, thereadability of barcodes is limited to certain positions within thatsmall scan volume

SUMMARY OF THE INVENTION

Thus, it would be desirable to provide an optical scanner which isoptically simple. It would also be desirable to produce an opticalscanner which can address one or more of the problems detailed above.

In accordance with a first aspect of the present invention there isprovided an optical scanner comprising a scanner housing including ascan window, a laser light source, reflected light detector and aMicro-Electro-Mechanical Systems (MEMS) mirror array arranged to producea scan line pattern.

Preferably the light from the laser source is adjustably focused by theMEMS mirror array.

More preferably the focal length of the MEMS array is adjusted byadjusting a mirror control signal to each of the mirrors in the MEMSarray.

In one embodiment the scanner further comprises a resistor ladder,arranged such that the necessary mirror control signal can be providedto each mirror in the mirror array, to alter the focal length of themirror array, by providing a single array control signal.

Preferably the optical scanner is arranged to produce a scan patterncontaining curved scan lines, by control of the focal length andposition of the MEMS array.

Preferably the MEMS array is operable to form the curved scan lines intoa spiral scan pattern in which the distance from the MEMS array to thefocus of each of the lines is alterable.

Most preferably the focal length of the MEMS array can be altered duringa scanning process so as to auto-focus the scanner.

In one embodiment the optical scanner further comprises pattern mirrorsarranged to direct light from the MEMS mirror array through the scanwindow so as to produce scan lines.

Most preferably the optical scanner further comprises control circuitryin the scanner housing for obtaining bar code information fromelectrical signals from the reflected light detector.

In accordance with a second aspect of the present invention there isprovided an optical scanner comprising a scanner housing including ascan window, a laser light source, reflected light detector and aMicro-Electro-Mechanical Systems (MEMS) mirror array arranged to producea scan line pattern, wherein the light from the laser source isadjustably focused by the MEMS mirror array so as to enableauto-focusing of the laser light during the scanning of a bar code.

In accordance with a third aspect of the present invention there isprovided an optical scanner comprising a scanner housing including ascan window, a laser light source, reflected light detector and aMicro-Electro-Mechanical Systems (MEMS) mirror array arranged to producea scan line pattern including curved scan lines.

In accordance with a fourth aspect of the present invention there isprovided a method of scanning a bar code utilizing an optical scannercomprising a scanner housing including a scan window, a laser lightsource, reflected light detector and a Micro-Electro-Mechanical Systems(MEMS) mirror array arranged to produce a scan line pattern, wherein thelight from the laser source is adjustably focused by the MEMS mirrorarray so as to enable auto-focusing of the laser light during thescanning of a bar code,

the method comprising allowing a bar code to be located substantially infront of the scan window and adjusting the focal length of the lightfrom the laser light source until the detector detects light reflectedfrom the bar code.

Preferably the focal length of the MEMS array is adjusted by adjusting amirror control signal to each of the mirrors in the MEMS array.

Most preferably a resistor ladder is arranged such that the necessarymirror control signal is provided to each mirror in the mirror array, toalter the focal length of the mirror array, by providing a single arraycontrol signal.

In one embodiment the MEMS array is controlled to produce a scan patterncontaining curved scan lines, by control of the focal length andposition of the MEMS array.

Most preferably the MEMS array is controlled to form the curved scanlines into a spiral scan pattern in which the distance from the MEMSarray to the focus of the lines is alterable.

Preferably bar code information is produced from electrical signals,produced by control circuitry in the scanner housing, from the lightreflected from each bar code.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of a prior art dual aperture scanner will now bedescribed, by way of example, with reference to the accompanyingdrawings, in which:

FIG. 1 is a block diagram of the optical scanner having enhanced itemside coverage of the present invention;

FIG. 2 is an exterior perspective view of the scanner of the presentinvention, including a reference coordinate system for the group ofpattern mirrors within the scanner of the present invention;

FIG. 3 is an interior perspective view of the scanner of the presentinvention, showing horizontal and vertical scanner portions;

FIG. 4 is a sectional view of the scanner of the present invention alonglines 4-4 of FIG. 3;

FIG. 5 is a top view of a horizontal mirror basket within a horizontaloptics assembly; and

FIG. 6 is a schematic illustration of the scan pattern from thehorizontal window of a prior art dual aperture scanner.

Thereafter embodiments of the present invention will be described, byway of example, with reference to the accompanying drawings, in which:

FIG. 7 is MEMS mirror array for use in an optical scanner in accordancewith the present invention;

FIG. 8 is a MEMES gear actuator for positioning a mirror in the MEMSmirror array of FIG. 7;

FIG. 9 is a schematic representation of MEMS mirror array focusing alaser beam;

FIG. 10 is schematic representation of the MEMS mirror array of FIG. 9arranged to produce variable focusing of the laser beam;

FIG. 11 is a schematic representation of the array of FIGS. 9 & 10arranged to operate with a single array control signal, which whenapplied controls the position of all of the mirrors in the array so asto adjustably focus the laser light;

FIG. 12 is a schematic representation of the MEMS mirror array of FIGS.9 to 11 with a 2 dimensional actuator, arranged to controllably alterthe position of the array within the scanner housing; and

FIG. 13 is a schematic representation of one embodiment of an opticalscanner in accordance with the present invention.

DETAILED DESCRIPTION

Referring now to FIG. 1, prior art dual aperture optical scanner 10includes horizontal optics assembly 12H and vertical optics assembly12V, and control circuitry 36 for controlling horizontal and verticaloptics assemblies 12H and 12V. If one of optics assemblies 12H and 12Vfails, scanner 10 retains partial operation.

Horizontal optics assembly 12H projects a scan pattern throughsubstantially horizontal aperture 34H to scan bar codes 42 located onbottom, leading, trailing and checker side surfaces of item 40. It willalso scan bar codes 42 on intermediate surfaces including those betweenthe bottom and customer side surfaces.

Horizontal optics assembly 12H includes laser 16H, aiming mirror 18H,polygon mirrored spinner 20H, pattern mirrors 22H, routing mirror 26H,collection optic 24H, detector assembly 28H, detection circuitry 30H,and motor 32H.

Laser 16H includes one or more laser diodes or other suitable lasersources. Laser 16H may include a laser having a wavelength of 650 nm.

Aiming mirror 18H aims a laser beam from laser 16H to polygon mirroredspinner 20H. The laser beam passes through a hole 25H in collectionoptic 24H (FIG. 4).

Polygon mirrored spinner 20H directs the laser beam to pattern mirrors22H. Polygon mirrored spinner 20H also routes collected light tocollection optic 24H. Polygon mirrored spinner 20H preferably includesfour facets, but may include other numbers of facets. Facets are groupedinto two pairs. Two opposite facets have angles of 74 degrees and 76degrees from the spinner base. The other pair of opposite facets hasangles of 86.5 degrees and 88.5 degrees. Motor 32H rotates polygonmirrored spinner 20H.

Pattern mirrors 22H produce scanning light beams that emanate fromsubstantially horizontal aperture 34H to form a horizontal scan patternfor reading bar code 42 on item 40. Pattern mirrors 22H also collectlight reflected from item 40 and direct it to polygon mirrored spinner20H.

Collection optic 24H routes collected light from polygon mirroredspinner 20H to routing mirror 26H.

Routing mirror 26H routes the collected light to detector assembly 28H.

Detector assembly 28H focuses, optically filters, and converts collectedlight into electrical signals.

Detection circuitry 30H obtains bar code information from the electricalsignals. Detection circuitry 30H includes circuitry for digitizing barcode information.

Vertical optics assembly 12V projects a scan pattern from substantiallyvertical aperture 34V and primarily scans bar codes located on acustomer side and top side of an item. Like horizontal optics assembly12H, vertical optics assembly 12V scans the leading and trailing sides,as well as intermediate surfaces including those between the bottom andcustomer side surfaces. However, for simplicity the substantiallysimilar vertical assembly will not be described in detail herein.

Control circuitry 36 processes the electrical signals from detectorassemblies 28H and assembly 28V to obtain bar code information. Controlcircuitry 36 passes the bar code information to POS terminal 14.

Control circuitry 36 controls operation of lasers 16H and 16V and motors32H and 32V. Control circuitry 36 may remove power from lasers 16H and16V and motors 32H and 32V to increase their longevity.

POS terminal 14 receives transaction data, for example, in the form ofSKU numbers from scanner 10 and completes a transaction by finding pricedata for the SKU numbers in a price-lookup data file.

Turning now to FIG. 2, scanner 10 is shown in perspective.

Scanner 10 as illustrated includes an integral scale 60. Scale 60includes weigh plate 62, which includes substantially horizontal surface50 and substantially horizontal aperture 34H. Horizontal window 64H islocated within horizontal aperture 34H.

Substantially vertical aperture 34V is located within substantiallyvertical surface 54. Substantially vertical window 64V is located withinsubstantially vertical aperture 34V.

Scanner 10 includes housing 52. Preferably, housing 52 may be easilyadapted to fit in a typical checkout counter 56. It is envisioned thatsubstantially horizontal surface 50 be made substantially flush with topsurface 58 of counter 56. Scanner 10 is installed within checkoutcounter 56 so that substantially vertical aperture 34V faces a storeemployee or other operator.

An illustrated reference X-Y-Z coordinate system determines orientationsof pattern mirrors 22H and 22V within scanner 10 of the presentinvention. Origin O is defined such that:

X=0 is on the centerline of the scanner;

Z=0 is on the centerline of the scanner; and

Y=0 is on the substantially horizontal surface 50.

Referring now to FIGS. 3-4, horizontal optics assembly 12H and verticaloptics assembly 12V are shown in their positions within housing 52.

Horizontal optics assembly 12H and vertical optics assembly 12V eachhave nearly all of the optical components of a functional bar codescanner. Horizontal optics assembly 12H and vertical optics assembly 12Veach have their own housings 66H and 66V and printed circuit boards 68Hand 68V. In the illustrated example, control circuitry 36 is located inhorizontal optics assembly 12H and signals vertical optics assembly 12Vare brought to control circuitry 36 via cables 69.

Horizontal optics assembly 12H includes horizontal aperture 35H andwindow 65H. Scale weigh plate 62 with horizontal aperture 34H and window64H are located above window 65H.

Horizontal optics assembly 12H will scan all label orientations on thebottom and checker sides of item 40, as well as certain orientations onthe leading and trailing sides.

Optical pathing between laser 16H and polygon mirrored spinner 20Havoids contacting pattern mirrors 22H along the way. Laser 16H islocated on a checker side of horizontal optics assembly 12H and polygonmirrored spinner 20H is located on the opposite side. Collection optic24H is located adjacent laser 16H. The laser beam from laser 16H passesthrough hole 25H in collection optic 24H. Detector assembly 28H islocated between collection optic 24H and polygon mirrored spinner 20H.

Spinners 20H and 20V are located where they are in order to generatesuitable scan lines. In optics assembly 12H, the generation of the frontvertical lines requires arcs of light reflected from a spinner 20H onthe back side of the optical cavity.

Substantially vertical aperture 34V is oriented at an acute angle T ofabout 86 degrees from substantially horizontal aperture 34H. Otherangular configurations, acute and obtuse, are also anticipated by thepresent invention.

Operationally, lasers 16H and 16V emit laser beams onto aiming mirrors18H and 18V, which reflect the laser beams through holes 25H and 25V incollection optics 24H and 24V and then onto mirrored polygon spinners20H and 20V. The polygon facets further reflect the laser beams up ordown (for horizontal assembly 12H) or forward or rearward (for verticalassembly 12V), depending upon the facet struck. As the facets rotate,the laser beams are scanned in a shallow arc and reflected onto patternmirrors 22H and 22V. In some cases, primary pattern mirrors reflect thelaser beams through apertures 34H and 34V onto surfaces of item 40. Inother cases, the primary pattern mirrors reflect the laser beams ontosecondary mirrors that reflect the laser beams through apertures 34H and34V onto surfaces of item 40.

As item 40 is moved through the scan zone (above horizontal aperture 34Hand in front of vertical aperture 34V), scan lines generated by thelaser beams from horizontal and vertical apertures 34H and 34V strikebar code label 42, no matter where it is located on item 42. A scan linewill pass through all or part of bar code label 40.

Item 42 scatters light back along the path of the incident laser light.The scattered light passes through horizontal and vertical apertures 34Hand 34V, onto the secondary mirrors (if present), onto the primarymirrors and onto the polygon facets. The rotating facets reflect thescattered light onto collection optics 24H and 24V. Collection optics24H and 24V focus the scattered light onto detector assemblies 28H and28V by way of routing mirrors 26H and 26V. Detector assemblies 28H and28V convert the scattered light into electrical signals for analogprocessing by pre-video circuitries 30H and 30V and digital processingby control circuitry 36.

Referring now to FIG. 5, pattern mirrors 22H are shown in detail.Horizontal pattern mirrors 22H include primary pattern mirrors andsecondary pattern mirrors. The primary pattern mirrors receive a laserbeam directly from spinner 20H. The secondary mirrors receive the laserbeam from some of the primary pattern mirrors.

The term “front” as applied to mirrors means operator or checker side.The term “rear” as applied to mirrors means the side opposite to theoperator or checker side. As illustrated, horizontal pattern mirrors 22Hexhibit substantially bilateral symmetry between the leading andtrailing sides of horizontal optics assembly 12H.

The primary pattern mirrors include left rear diagonal mirror 86, rightrear diagonal mirror 88, left front vertical mirror 78, right frontvertical mirror 80, left horizontal mirror 82, right horizontal mirror84, left front picket mirror 70, right front picket mirror 72, leftfront diagonal mirror 102, right front diagonal mirror 104, left frontbottom picket mirror 74, and right front bottom picket 76.

The secondary pattern mirrors include left rear diagonal mirror 94,right rear diagonal mirror 96, left front vertical mirror 90, rightfront vertical mirror 92, left horizontal mirror 98, and righthorizontal mirror 100.

With reference to FIGS. 7 to 12, we will now turn to a detailedexplanation of scanners in accordance with the present invention.

The heart of this invention is an array of Micro-Electro-MechanicalSystems, or MEMS. MEMS is a nano-fabrication technology which providesthe capability of merging mechanical functions like gears, valves, andmirrors with electronic actuator circuits on an extremely small scale(FIGS. 7 & 8). MEMS are commonly used in DLP computer projectors, usingtiny mirrors to block or reflect light for thousands of individualpixels.

A coordinated array 200 of MEMS mirrors 212 is utilized to focus a laserbeam 214 or other light source (See FIG. 9). By applying a definedcontrol voltage 216 to each mirror element 212, it can be positioned toreflect light towards a specific spot (A or B, FIG. 10). If all mirrorsdirect light to the same spot, then the resulting beam of light will be“in focus” at that spot. By changing the positions of the mirrors in acoordinated fashion, the focal distance can be changed. In oneembodiment, a finished assembly will consist of a round pattern ofmirror elements, arranged as a set of concentric circles. Such an arraywould act very similarly to a conventional optical variable-focus lens.FIG. 7 shows a rectangular MEMS mirror array provided on a FLAT siliconwafer and therefore requiring very little space.

Controlling the position of each mirror element in the array is donewith a set of electrical signals 216 generated by a computerized system.

In the electrical “drive” circuitry 218 of FIG. 11 only a single controlsignal is used to set the focal length of the entire array 200. A simpleresistor ladder 220 is utilized to provide the necessary voltage to eachmirror element 212 from a single input signal. One merely needs tofine-tune the values of the resistors to synchronize the deflections ofthe individual MEMS mirrors. After the system is calibrated, the mirroracts like an optical lens with a moving element. The result is areflected beam of light 222 with extremely accurate focus at a widerange of focal lengths.

Once we have the above array 200 of mirror elements 212 which can beeasily and accurately focused, we can change that focus in “real-time”and at high speeds. This is the second step in designing a MEMS scannerdevice. As the beam travels through space to create a “scan pattern,”the mirrors can be dynamically focused to maintain a very highresolution for reading small barcodes, etc.

The final step in applying this concept to a scanner is to mount theentire MEMS assembly onto a 2D actuator 224 (FIG. 12), which can movethe beam in a pre-defined pattern. One must remember that the entireMEMS assembly is tiny and light—perhaps a few millimeters square. The 2Dactuator can therefore be, for example, a pair of very small servomotors or even another set of MEMS devices. By using a second set ofcontrol voltages to move the array mechanism, it is possible to createvirtually any scan pattern—the current set of intersecting lines, aconcentric set of circles, or even a spiral in which the focal lengthincreases or decreases during the scan process, etc. The light source236 may need to be rigidly attached to the actuator 224 so as to movewith the MEMS array to maintain its focus

This ability substantially increases the read rate of barcodes despitetheir decreasing feature size. As the scan pattern gets bigger, though,the focal distance of the beam will vary substantially. This is wherethe initial concept of the dynamically focused mirror array becomescritical.

In addition, it is feasible to scan a 3D volume, instead of justcreating a 2D pattern of lines. By repeating the scan pattern (e.g. aspiral) at various focal distances, objects/barcodes could potentiallybe detected at much larger distances without sacrificing the ability toread objects close to the scanner. In practice, this “auto-focusing”capability requires a sequence of scans, each one with the mirror arrayset for an increasing focal length. Given the speed of modern computingand MEMS technologies, is imperceptible to the operator or customer.

FIG. 13 illustrates an optical scanner 230 comprising a scanner housing232 including a scan window 234. The scanner housing 232 is partiallycut away to allow a view of the inside of the housing. The scannerfurther includes a laser light source 236 and a reflected light detector238 for detecting light reflected from a bar code 240 located outsidethe housing 232. Finally the scanner includes a Micro-Electro-MechanicalSystems (MEMS) mirror array 242 arranged to produce a scan line patternoutside of the scan window 234. The light from the laser source 236 isadjustably focused by the MEMS mirror array 242. The focal length of theMEMS array is adjusted by adjusting a mirror control signal to each ofthe mirrors in the MEMS array, as described above.

In one embodiment the optical scanner can further comprising patternmirrors, such as those described in relation to the prior art scanner ofFIGS. 1 to 6, arranged to direct light from the MEMS mirror arraythrough the scan window so as to produce scan lines. Alternatively, asin FIG. 13, the light reflected and focused by the MEMS array can bedirected out of the scan window without the use of additional patternmirrors.

The optical scanner further comprises control circuitry 244 in thescanner housing 232 for obtaining bar code information from electricalsignals from the reflected light detector 238.

When in use the scanner described above can be utilized to scan a barcode located substantially in front of the scan window 234, by adjustingthe focal length of the light from the laser source until the detector238 detects light reflected from the bar code.

A scanner in accordance with the present invention will provide asimple, fast way to dynamically focus a beam of light (or laser beam) soas to scan a bar code. Furthermore it allows a scanner to compensate inreal-time for varying beam distances, which occur naturally in a laserscan pattern. Hence, it improves readability of small barcodes like theRSS symbology and enables a scanner to become essentially“auto-focusing” and read at a wider range of distances.

Due to the small size of MEMS devices a significantly smaller scanengine can be produced. Also, as a complex arrangement of patternmirrors is not necessary the scanner can be manufactured atsubstantially reduces cost compared to current scanners which utilizespinner motors and a large numbers of mirrors. Finally, the presentscanner provides many unique scan patterns with tighter line spacing(density).

The foregoing description of the preferred embodiments of the inventionhas been presented for the purposes of illustration and description. Itis not intended to be exhaustive or to limit the invention to theprecise form disclosed. Many modifications and variations are possiblein light of the above teaching within the spirit and scope of theinvention as claimed

1-12. (canceled)
 13. An optical scanner comprising a scanner housingincluding a scan window, a laser light source, reflected light detectorand a Micro-Electro-Mechanical Systems (MEMS) mirror array arranged toproduce a scan line pattern, wherein the light from the laser lightsource is adjustably focused by the MEMS mirror array so as to enableauto-focusing of the laser light during the scanning of a bar code. 14.The optical scanner of claim 13, wherein the focal length of the MEMSarray is adjusted by adjusting a mirror control signal to each of themirrors in the MEMS array.
 15. The optical scanner of claim 14, furthercomprising a resistor ladder, arranged such that the necessary mirrorcontrol signal is provided to each mirror in the mirror array, to alterthe focal length of the mirror array, by providing a single arraycontrol signal.
 16. The optical scanner of claim 13, arranged to producea scan pattern containing curved scan lines, by control of the focallength and position of the MEMS array.
 17. The optical scanner of claim16, wherein the MEMS array is operable to form the curved scan linesinto a spiral scan pattern in which the distance from the MEMS array tothe focus of the lines is alterable.
 18. The optical scanner of claim13, further comprising a 2-dimensional actuator, on which the MEMSmirror array is mounted, which is arranged to move the MEMS mirror arrayand thus create a plurality of different scan patterns.
 19. The opticalscanner of claim 18, wherein the actuator is formed from a pair ofservo-motors.
 20. The optical scanner of claim 18, wherein the actuatoris formed from additional MEMS motor devices.
 21. The optical scanner ofclaim 13, further comprising pattern mirrors arranged to direct lightfrom the MEMS mirror array through the scan window so as to produce scanlines.
 22. The optical scanner of claim 13, further comprising controlcircuitry in the scanner housing for obtaining bar code information fromelectrical signals from the reflected light detector.
 23. (canceled) 24.A method of scanning a bar code utilizing an optical scanner comprisinga scanner housing including a scan window, a laser light source,reflected light detector and a Micro-Electro-Mechanical Systems (MEMS)mirror array arranged to produce a scan line pattern, wherein the lightfrom the laser source is adjustably focused by the MEMS mirror array soas to enable auto-focusing of the laser light during the scanning of abar code, the method comprising allowing a bar code to be locatedsubstantially in front of the scan window and adjusting the focal lengthof the light from the laser source until the detector detects lightreflected from the bar code.
 25. The method of claim 24, wherein thefocal length of the MEMS array is adjusted by adjusting a mirror controlsignal to each of the mirrors in the MEMS array.
 26. The method of claim25, wherein a resistor ladder is arranged such that the necessary mirrorcontrol signal is provided to each mirror in the mirror array, to alterthe focal length of the mirror array, by providing a single arraycontrol signal.
 27. The method of claim 24, wherein the MEMS array iscontrolled to produce a scan pattern containing curved scan lines, bycontrol of the focal length and position of the MEMS array.
 28. Themethod of claim 27, wherein the MEMS array is controlled to form thecurved scan lines into a spiral scan pattern in which the distance fromthe MEMS array to the focus of the lines is alterable.
 29. The method ofclaim 24, further comprising locating the MEMS mirror array on a2-dimensional actuator and moving the MEMS mirror array so as to createa plurality of different scan patterns.
 30. The method of claim 29,wherein the actuator is formed from a pair of servo-motors.
 31. Themethod of claim 24, wherein the actuator is formed from additional MEMSmotor devices.
 32. The method of claim 24, wherein bar code informationis produced from electrical signals, produced by control circuitry inthe scanner housing, from the light reflected from each bar code.
 33. Amethod of scanning a bar code, comprising: generating light with a lightsource; reflecting light generated by the light source with aMicro-Electro-Mechanical Systems (MEMS) mirror array; moving the MEMSmirror array during the reflecting step to generate a repeating scanpattern of light; altering focal length of light reflected by the MEMSmirror array during the moving step. positioning an object bearing a barcode into light reflected by the MEMS mirror array during the alteringand moving steps so that light is reflected off the object bearing thebar code; and generating bar code information in response receipt oflight reflected off the object bearing the bar code.
 34. The method ofclaim 33, wherein the altering step includes changing the arrangement ofthe MEMS mirror array between (i) a first configuration in which lightreflected by the MEMS mirror array possesses a first focal length, and(ii) a second configuration in which light reflected by the MEMS mirrorarray possesses a second focal length which is different from the firstfocal length.
 35. The method of claim 34, wherein: the MEMS mirror arrayincludes a plurality of mirror elements that are configurable betweenthe first configuration and the second configuration, and the alteringstep includes (i) providing a control signal to each of the plurality ofmirror elements, and (ii) moving the plurality of mirror elements fromthe first configuration to the second configuration in response toreceipt of the control signal.
 36. The method of claim 35, wherein thealtering step further includes generating the control signal with aresistor ladder circuit.
 37. The method of claim 33, wherein the barcode generating step includes: receiving light reflected off the objectbearing the bar code with a reflected light detector and generatingelectrical signals in response thereto; and generating bar codeinformation based on the electrical signals.
 38. An optical scanner,comprising: a light source operable to generate light; aMicro-Electro-Mechanical Systems (MEMS) mirror array positioned toreflect light generated by said light source, said MEMS mirror arraybeing movable between (i) a first configuration in which light reflectedby said MEMS mirror array possesses a first focal length, and (ii) asecond configuration in which light reflected by said MEMS mirror arraypossesses a second focal length which is different from said first focallength; an actuator coupled to said MEMS mirror array and operable tomove said MEMS mirror array while said MEMS mirror array is reflectinglight generated by said light source so that a repeating scan pattern oflight is produced; a reflected light detector (i) positioned to receivelight reflected off an object bearing a bar code that is located in apath of light being reflected off said MEMS mirror array, and (ii)operable to generate electrical signals in response to receipt of lightbeing reflected off the object bearing the bar code; and circuitryoperable to (i) receive said electrical signals generated by saidreflected light detector, and (ii) generate bar code information inresponse thereto.
 39. The optical scanner of claim 38, furthercomprising a controller operable to generate control signals, wherein:said MEMS mirror array includes a plurality of mirror elements that areconfigurable between said first configuration and said secondconfiguration, and said plurality of mirror elements move between saidfirst configuration and said second configuration in response togeneration of said control signals.
 40. The optical scanner of claim 39,wherein said controller includes a resistor ladder circuit.
 41. Theoptical scanner of claim 38, wherein said actuator includes a servomotor apparatus.
 42. A method of scanning a bar code, comprising:generating light with a light source; reflecting light generated by thelight source with a Micro-Electro-Mechanical Systems (MEMS) mirrorarray; moving the MEMS mirror array during the reflecting step togenerate a repeating scan pattern of light; and altering focal length oflight reflected by the MEMS mirror array.
 43. The method of claim 42,further comprising generating bar code information in response receiptof light reflected off an object bearing a bar code that is located in apath of light being reflected off the MEMS mirror array.
 44. The methodof claim 42, wherein the altering step includes changing the arrangementof the MEMS mirror array between (i) a first configuration in whichlight reflected by the MEMS mirror array possesses a first focal length,and (ii) a second configuration in which light reflected by the MEMSmirror array possesses a second focal length which is different from thefirst focal length.
 45. The method of claim 42, wherein: the MEMS mirrorarray includes a plurality of mirror elements, and the altering stepincludes (i) generating a control signal, and (ii) moving the pluralityof mirror elements in response to generation of the control signal. 46.The method of claim 45, wherein the altering step further includesgenerating the control signal with a resistor ladder circuit.
 47. Themethod of claim 42, further comprising: receiving light reflected off anobject bearing a bar code with a reflected light detector and generatingelectrical signals in response thereto; and generating bar codeinformation based on the electrical signals.
 48. The method of claim 42,wherein said altering step is performed during said moving step.